摘要
东海盆地西湖凹陷西斜坡平湖组地层埋藏深度大,沉积环境复杂,砂体横向变化大,且普遍发育的煤层具有厚度薄、层数多、范围广的特征,砂、泥、煤岩性组合多样,导致储层的地震响应规律认识不清,常规的叠后地震振幅及波阻抗反演已经不能满足储层刻画的需求。针对上述问题,由实钻井资料统计了11种砂、泥、煤的典型组合模式,结合AVO理论进行叠前地震正演模拟,从而总结储层地震响应规律。发现在不同岩性组合的情况下,AVO的梯度属性依然能够稳定地表征储层,对梯度属性进行90°相移,其结果能更直观地进行储层的刻画,并且与实钻井吻合度较高,对P5层的平面展布预测符合平湖组潮坪沉积的地质认识。基于地震振幅的梯度属性结合90°相移准确预测了含煤地层中的储层,为西湖凹陷岩性油气藏的勘探提供了有力支持。
The Pinghu formation in the western slope of the Xihu sag in East China Sea Basin has a large burial depth,a complex depositional environment,and large lateral changes in sand bodies.The generally developed coal seams have the characteristics of thin thickness,multiple layers,and wide ranges,with diverse combinations of sand,mud,and coal.As a result,the understanding of the law of the seismic response of the reservoir is unclear,and the conventional post-stack seismic amplitude and acoustic impedance inversion can no longer meet the needs of reservoir characterization.In response to the above-mentioned problems,eleven typical combinations of sand,mud,and coal are counted from actual drilling data,and the AVO theory is used to carry out forward modeling of pre-stack seismic.Summarized the laws of the seismic response of the reservoir.In the case of different lithological combinations,the gradient attributes of AVO can still stably characterize the reservoir.The 90°phase shift of the gradient attributes can provide a more intuitive description of the reservoir and a higher degree of agreement with actual drilling.The prediction of the plane distribution of the P5 layer conforms to the geological understanding of the tidal flat deposits of the Pinghu formation.The gradient attribute based on the seismic amplitude combined with the 90°phase shift accurately predicts the reservoir in the coal-bearing strata,which provides strong support for the exploration of lithologic oil and gas reservoirs in the Xihu sag.
作者
胡伟
俞伟哲
张岩
刘庆文
黄鋆
HU Wei;YU Weizhe;ZHANG Yan;LIU Qingwen;HUANG Jun(Shanghai Branch of CNOOC Co.Ltd.,Shanghai 200335,China)
出处
《上海国土资源》
2022年第1期75-79,共5页
Shanghai Land & Resources
基金
“十三五”国家科技重大专项“东海深层低渗—致密天然气勘探开发技术”(2016ZX05027001)。
关键词
东海盆地
地震勘探
AVO理论
梯度属性
90°相移
含煤地层
储层预测
East China Sea Basin
seismic exploration
AVO theory
gradient attribute
90°phase shift
coal-bearing strata
reservoir prediction
